The present invention generally relates to turbochargers. More particularly, the present invention relates to a turbocharger system having first and second turbochargers each having an air intake impeller which rotate in opposite directions, so that the turbochargers can be arranged in a symmetrical fashion with respect to the engine block, and provide engine performance benefits.
A turbocharger is an exhaust gas-driven compressor used to increase the power output of an internal-combustion engine by compressing air that is entering the engine, thus increasing the amount of available oxygen. Turbochargers can offer a considerable increase in engine power with only a slight increase in weight.
The mechanical concept of a turbocharger revolves around three main parts. A turbine is driven by the exhaust gas of an internal combustion engine to spin an impeller whose function is to force more air into the engine's intake, or air supply. A central hub rotating assembly includes a rod extending between the turbine and the impeller, and includes bearings, lubrication, cooling, etc. to enable it to rotate at high speeds. The exhaust turbine is contained within an exhaust portion, or folded conical housing, on one side of the center hub rotating assembly, while the impeller is contained within its own folded conical housing intake air compressor portion on the opposite side of the center hub rotating assembly. These housings or portions collect and direct the gas flow.
More particularly, as illustrated in FIG. 1, the exhaust portion or housing 12 and 22 of each turbocharger 10 and 20 includes an exhaust gas inlet 14 and 24 which is operably connected to exhaust pipes 32 and 34 extending from the exhaust outlets of the engine 30. The exhaust gases, under pressure, impinge upon front faces of a plurality of blades of the turbine, causing it to spin. If the pressure of the exhaust gases becomes too great and/or the turbine spins too rapidly, a wastegate 36 and 38 is typically provided so as to vent exhaust gas or redirect the exhaust gas such that it is not directed against the turbine.
The spinning of the exhaust turbine by the exhaust gases causes the shaft or rod within the center hub rotating assembly to rotate, thus rotating the impeller 16 and 26. The impeller has a plurality of blades configured such so as to have front faces which draw in air, and push the air in a direction so as to compress the air. This compressed air is then used in the internal combustion engine 30, which increases the efficiency of the engine, enables burning of additional fuel, and thus generates more power. Typically, only the downward stroke of a piston creates an area of low pressure in order to draw air into the cylinder. However, the turbocharger 10 or 20 increases the pressure at the point where air is entering the cylinder, and the amount of air brought into the cylinder is increased.
While performing generally adequately, there are disadvantages with the current turbochargers which have been traditionally used. That is, turbochargers have always been created in the past with impellers that rotate in a clockwise direction. The disadvantages of this arrangement are not readily apparent. However, due to the fact that the air intake impellers for both turbochargers 10 and 20 rotate clockwise, the first and second turbochargers 10 and 20 mounted onto an engine block are not symmetrical. For example, as illustrated in FIG. 1, a V-block engine 30 is shown with prior art turbochargers 10 and 20 installed thereon. Those skilled in the art will appreciate that a V-block engine refers to an engine having cylinders and pistons angled with respect to another so as to create a generally V-shape, such as a V-6, V-8, etc. engine block. On one side of the engine 30 the exhaust pipes 32 extend from the exhaust outlets of these cylinders and extend to the exhaust intake port 14 of the first turbocharger 10. Similarly, exhaust pipes 34 extend from exhaust outlets of the cylinders on the opposite side of the engine 30 to the exhaust intake port 24 of the second turbocharger 20. Also, air intake pipes 40 and 42 are attached to the air intake ports 18 and 28 of each of the first and second turbochargers 10 and 20. Due to the fact that the air intake impellers 16 and 26 of each turbocharger rotate in a clockwise direction, the first and second turbochargers 10 and 20 must be installed and arranged in an asymmetrical fashion. This is undesirable aesthetically.
Moreover, as shown in FIG. 1, the configuration and the lengths of the exhaust pipes 32 and 34 extending from the engine 30 to the first and second turbochargers 10 and 20 are not the same. In the illustrated example, the exhaust pipe 34 connected to the turbocharger 20 on the right-hand side of the engine 30 has much more dramatic bends than those on the left-hand side of the engine 30. Typically, the air intake pipes 40 and 42 are also of a different configuration and length, such as the air intake pipe 42 on the right-hand side having bends whereas the intake pipe 40 in the left is generally straight. The difference in lengths and bends in the intake and exhaust piping create a negative impact on the engine. In fact, after installing turbochargers on an engine, it is necessary to take these differences into account when tuning the engine so as to obtain optimal engine performance.
Accordingly, there is a continuing need to provide a turbocharger system in which the first and second turbocharger impellers rotate in opposite directions, such that the turbochargers can be installed symmetrically in order to overcome the aforementioned disadvantages. The present invention fulfills these needs, and provides other related advantages.